JP2009063975A - Discharger, image holder unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce sticking of discharge product to the surface of the electrode member. <P>SOLUTION: The occurrence of rust of the net-like electrode member 12 is reduced by a ta-C surface layer which has oxidation resistance and low reactivity. In addition, the ta-C surface is smooth. Therefore, even if discharge product sticks to the member, the mechanical bonding force of it is small. A heating device heats the surface of the net-like electrode member 12 in which the ta-C surface layer is formed. Thereby, discharge product sticking to the surface of the net-like electrode member 12 is evaporated and ejected from the surface of the net-like electrode member 12. This makes it possible to reduce sticking of discharge product to the surface of the electrode member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a discharger, an image carrier unit, and an image forming apparatus.

  In conventional image forming apparatuses such as electrophotographic copying machines and printers, the surface of an image carrier such as a photoreceptor is charged by a charger, and an electrostatic latent image is formed and developed on the charged image carrier surface. It was transferred to a medium to form an image.

  As the charger, a contact-type charger that is rotated in contact with or in proximity to the image carrier, a so-called charging roller, and the surface of the image carrier by discharge between the electrodes arranged opposite to the image carrier. Non-contact discharge type chargers for charging, so-called corotrons and scorotrons, are widely used. As the non-contact discharge type charger, techniques described in Patent Documents 1 to 3 below are conventionally known.

  Patent Document 1 describes a charging device in which both sides of a plate-like discharge electrode are covered with an insulating dielectric in order to reduce the amount of discharge products generated and extend the life. Patent Document 1 also describes a cleaning member that cleans an exposed portion of the discharge electrode.

  In Patent Document 2, in order to prevent the occurrence of rust on the surface of the plate-like grid due to the discharge product, the surface of the grid substrate of the plate-like grid is uniformly applied by a conductive paint spray method including graphite, A technique for forming a conductive layer is described.

In Patent Document 3, in order to suppress the occurrence of image defects such as image density change and image unevenness under the charger of the photoreceptor, graphite particles, nickel particles, and aluminum compounds are formed on the substrate surface of the control electrode of the corona discharger. An invention for forming a conductive film including conductive particles made of one or a plurality of particles is described.
JP 2002-268334 A JP 2004-198909 A JP 2005-227470 A

  An object of this invention is to reduce adhesion of the discharge product to the surface of an electrode member.

  According to a first aspect of the present invention, there is provided a discharge device comprising: a discharge electrode member disposed opposite to a member to be charged; a counter electrode member disposed opposite the discharge electrode member; and the discharge electrode member opposed to the discharge electrode member. A power supply circuit that applies a discharge voltage that generates a discharge between the electrode member and at least one surface of the discharge electrode member and the counter electrode member; and carbon atoms, or carbon atoms and other desired atoms or It is characterized by comprising: a coating material having an SP3 structure of carbon atoms with other plural atoms as main components; and a heating means for heating the surface coated with the coating material.

  According to a second aspect of the present invention, in the discharge device according to the first aspect, the heating means heats at the time of non-discharge when no discharge is generated between the discharge electrode member and the counter electrode member. It is characterized by.

  According to a third aspect of the present invention, in the discharge device according to the first or second aspect, the heating means determines a heating time based on a discharge time of the discharge electrode member.

  A discharger according to a fourth aspect of the present invention is the discharge device according to any one of the first to third aspects, wherein the heating temperature of the heating means is equal to or higher than the boiling point of the deposit attached to the surface heated by the heating means. It is characterized by being.

  According to a fifth aspect of the present invention, there is provided a discharger according to any one of the first to fourth aspects, further comprising an electrode cleaning member for cleaning the surface heated by the heating means, wherein the heating means includes the electrode. The surface is heated before the cleaning member cleans.

  A discharger according to a sixth aspect of the present invention comprises the gas transfer device according to any one of the first to fifth aspects, wherein the gas transfer device is configured to transfer a gas along the surface covered with the coating material. Features.

  A discharger according to a seventh aspect of the present invention is the discharge device according to the sixth aspect, wherein the gas transfer device generates a gas during non-discharge when no discharge is generated between the discharge electrode member and the counter electrode member. It is transported.

  The discharger according to an eighth aspect of the present invention is characterized in that, in the configuration of the sixth or seventh aspect, the gas transfer device determines a transfer time based on a discharge time of the discharge electrode member.

  According to a ninth aspect of the present invention, in the discharge device according to any one of the sixth to eighth aspects, the gas transfer device performs a discharge generated between the discharge electrode member and the counter electrode member. It is characterized in that the amount of gas transfer is larger during non-discharge when no discharge is generated between the discharge electrode member and the counter electrode member than during discharge.

  According to a tenth aspect of the present invention, there is provided an image carrier unit comprising: a charger constituted by the discharger according to any one of the first to ninth aspects; and the image when the heating means is heating the surface. And an image holding body as the charged body for rotating the holding body and holding the image on the surface thereof.

  An image carrier unit according to an eleventh aspect of the present invention includes a charger constituted by the discharger according to any one of the sixth to ninth aspects, and the gas transfer device transferring the gas. And an image holding body as the charged body for rotating the image holding body and holding the image on the surface thereof.

  An image carrier unit according to a twelfth aspect of the present invention is the image carrier unit according to the eleventh aspect, wherein the drive control unit controls the rotation speed of the image carrier according to the amount of the gas transferred by the gas transfer device. It is characterized by doing.

  According to a thirteenth aspect of the present invention, there is provided an image forming apparatus comprising the charger according to any one of the first to ninth aspects, and an image holding body as the charged body that holds an image on a surface thereof. A latent image forming apparatus that forms a latent image on the surface of the image carrier charged by the charger, a developing unit that develops the latent image formed on the surface of the image carrier into a visible image, and the image carrier. And a transfer device that transfers a visible image on the surface to a medium.

  According to the structure of Claim 1 of this invention, compared with the case where it does not have this structure, adhesion of the discharge product to the surface of an electrode member can be reduced.

  According to the structure of Claim 2 of this invention, compared with the case where it does not have this structure, adhesion of the discharge product to the surface of the electrode member at the time of non-discharge can be reduced efficiently.

  According to the structure of Claim 3 of this invention, compared with the case where it does not have this structure, adhesion of a discharge product can be reduced efficiently.

  According to the structure of Claim 4 of this invention, compared with the case where it does not have this structure, adhesion of a discharge product can be reduced effectively.

  According to the structure of Claim 5 of this invention, the cleaning property of a discharge product improves compared with the case where it does not have this structure.

  According to the configuration of the sixth aspect of the present invention, it is possible to reduce the adhesion of the discharge product to the charged body as compared with the case where the configuration is not provided.

  According to the structure of Claim 7 of this invention, compared with the case where it does not have this structure, adhesion of the discharge product to the to-be-charged body at the time of non-discharge can be reduced efficiently.

  According to the structure of Claim 8 of this invention, compared with the case where it does not have this structure, adhesion of the discharge product to a to-be-charged body can be reduced efficiently.

  According to the configuration of the ninth aspect of the present invention, it is possible to efficiently reduce the adhesion of the discharge product to the member to be charged at the time of non-discharge compared with the case where the present configuration is not provided.

  According to the structure of Claim 10 of this invention, compared with the case where it does not have this structure, adhesion of the discharge product to a to-be-charged body can be reduced.

  According to the configuration of the eleventh aspect of the present invention, the adhesion of the discharge product to the member to be charged can be reduced as compared with the case where the configuration is not provided.

  According to the structure of Claim 12 of this invention, compared with the case where it does not have this structure, adhesion of the discharge product to a to-be-charged body can be reduced efficiently.

  According to the structure of Claim 13 of this invention, compared with the case where it does not have this structure, adhesion of the discharge product to the surface of an electrode member can be reduced.

  Below, an example of an embodiment concerning the present invention is described based on a drawing.

  In order to facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and arrows X, -X, Y, -Y, The direction indicated by Z and -Z or the indicated side is defined as the front side, the rear side, the right side, the left side, the upper side, the lower side, or the front side, the rear side, the right side, the left side, the upper side, and the lower side, respectively.

  In addition, in the plan view showing the configuration two-dimensionally, “•” written in “○” means an arrow heading from the back to the front of the plan view, and “×” "" Means an arrow heading from the front to the back of the plan view.

(Configuration of image forming apparatus according to the present embodiment)
First, the configuration of the image forming apparatus according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present embodiment.

  As shown in FIG. 1, the image forming apparatus U includes a user interface UI as an example of an operation unit, an image input apparatus U1 as an example of an image information input apparatus, a paper feeding apparatus U2, an image forming apparatus main body U3, and sheet processing. It has a device U4.

  The user interface UI includes an input key such as a copy start key, a copy number setting key, a numeric keypad, and a display unit UI1.

  The image input device U1 includes an automatic document feeder and an image scanner as an example of an image reading device. The image input device U1 reads a document (not shown), converts it into image information, and inputs it to the image forming apparatus body U3.

  The sheet feeding device U2 is a recording sheet as an example of a plurality of sheet feeding units TR1, TR2, TR3, TR4, and a medium accommodated in each of the sheet feeding trays TR1, TR2, TR3, TR4. A sheet feed path SH1 for taking out S and transporting it to the image forming apparatus main body U3 is provided.

  The image forming apparatus main body U3 includes an image recording unit that records an image on the recording sheet S conveyed from the sheet feeding device U2, a toner dispenser device U3a, a sheet conveying path SH2, a sheet discharging path SH3, a sheet reversing path SH4, a sheet It has a circulation path SH6 and the like. The image recording unit will be described later.

  The image forming apparatus main body U3 includes a control unit C, a laser drive circuit D as an example of a latent image writing device drive circuit controlled by the control unit C, and a power supply circuit E controlled by the control unit C. Etc. The laser drive circuit D whose operation is controlled by the control unit C is a laser corresponding to image information of Y (yellow), M (magenta), C (cyan), and K (black) input from the image input device U1. Drive signals are output to the latent image forming apparatuses ROSy, ROSm, ROSc, and ROSk of the respective colors at a predetermined timing.

  Below each of the latent image forming apparatuses ROSy, ROSm, ROSc, and ROSk of the respective colors, a drawing position where the drawing member U3b for the image forming unit is drawn to the front of the image forming apparatus main body U3 by the pair of left and right guide members R1 and R1. And a mounting position mounted in the image forming apparatus main body U3.

  FIG. 2 is a schematic diagram showing the configuration of the image carrier unit according to the present embodiment. 1 and 2, a black image carrier unit UK includes a photosensitive drum Pk as an example of an image carrier that holds an image on the surface, a charger CCk, and a cleaner as an example of an image carrier cleaner. CLk.

  The photosensitive drum Pk has a diameter of 60 mm, for example, and can form an image at a maximum speed of 320 mm / sec using other peripheral process devices.

  In the present embodiment, the cleaner CLk is constituted by a cleaner unit. The other color (Y, M, C) image carrier units UY, UM, UC are also provided with the photosensitive drums Py, Pm, Pc, chargers CCy, CCm, CCc, cleaners CLy, CLm, CLc.

  The toner image forming members (UY + GY), (UM + GM), (UC + GC) are constituted by the developing units GY, GM, GC, GK having the image carrier units UY, UM, UC, UK and the developing roll R0 (see FIG. 2). , (UK + GK). The image forming unit drawing member U3b (see FIG. 1) is detachably mounted with the image carrier units UY, UM, UC, UK and developing units GY, GM, GC, GK.

  In FIG. 1, photosensitive drums Py, Pm, Pc, and Pk are uniformly charged by chargers CCy, CCm, CCc, and CCk, respectively, and then output from the latent image forming devices ROSy, ROSm, ROSc, and ROSk. An electrostatic latent image is formed on the surface of the laser beam Ly, Lm, Lc, Lk as an example of the latent image writing light. The electrostatic latent images on the surfaces of the photosensitive drums Py, Pm, Pc, and Pk are Y (yellow), M (magenta), C (cyan), and K (black) colors by developing units GY, GM, GC, and GK. The toner image is developed.

  The toner images on the surfaces of the photosensitive drums Py, Pm, Pc, and Pk are transferred onto an intermediate transfer belt B as an example of an intermediate transfer member by primary transfer rolls T1y, T1m, T1c, and T1k as an example of a primary transfer unit. The images are sequentially superimposed and transferred, and a multicolor image, so-called color image, is formed on the intermediate transfer belt B. The color image formed on the intermediate transfer belt B is conveyed to the secondary transfer area (image recording position) Q4.

  In the case of only black image data, only the K (black) photosensitive drum Pk and the developing device GK are used, and only a black toner image is formed.

  As shown in FIG. 2, a charger PCCk for adjusting the charging potential of the photosensitive drum Pk is disposed between the primary transfer roll T1k and the cleaner CLk so as to facilitate cleaning by the cleaner CLk. Although not shown, the photosensitive drums Py, Pm, and Pc are charged between the primary transfer rolls T1y, T1m, and T1c and the cleaners CLy, CLm, and CLc in order to facilitate cleaning with the cleaners CLy, CLm, and CLc. Chargers for adjusting the potentials are respectively arranged.

  After the primary transfer, residual toner on the surface of the photosensitive drums Py, Pm, Pc, and Pk is cleaned by the cleaners CLy, CLm, CLc, and CLk for the photosensitive drums.

  Below the image forming unit drawing member U3b, there is a space between the drawing position where the intermediate transfer member drawing member U3c is drawn to the front of the image forming apparatus body U3 and the mounting position where the image forming apparatus body U3 is mounted. It is supported so that it can move. The intermediate transfer member pull-out member U3c allows the belt module BM as an example of an intermediate transfer device to come into contact with the lower surface of the photosensitive drums Py, Pm, Pc, and Pk and to move down from the lower surface. It is supported so that it can move up and down.

  The belt module BM includes the intermediate transfer belt B, a belt support roll (Rd, Rt, Rw, Rf, T2a) as an example of an intermediate transfer member support member, and the primary transfer rolls T1y, T1m, T1c, T1k. And have. The belt support roll (Rd, Rt, Rw, Rf, T2a) includes a belt drive roll Rd as an example of an intermediate transfer member drive member, a tension roll Rt as an example of a tension applying member, and a walking roll as an example of a meandering prevention member. Rw, a plurality of idler rolls Rf as an example of a driven member, and a backup roll T2a as an example of a secondary transfer counter member. The intermediate transfer belt B is supported by the belt support rolls (Rd, Rt, Rw, Rf, T2a) so as to be rotatable in the arrow Ya direction.

  A secondary transfer unit Ut is disposed below the backup roll T2a. A secondary transfer roll T2b as an example of a secondary transfer member of the secondary transfer unit Ut is disposed so as to be separated from and contactable with the backup roll T2a with the intermediate transfer belt B interposed therebetween. The secondary transfer roll T2b is A secondary transfer region Q4 is formed by the region in pressure contact with the intermediate transfer belt B.

  Further, a contact roll T2c as an example of a voltage application contact member is in contact with the backup roll T2a, and a secondary transfer device T2 is constituted by the rolls T2a to T2c.

  A secondary transfer voltage having the same polarity as the charging polarity of the toner is applied to the contact roll T2c from the power supply circuit controlled by the control unit C at a predetermined timing.

  A sheet transport path SH2 is disposed below the belt module BM. The recording sheet S fed from the sheet feeding path SH1 of the sheet feeding device U2 is conveyed to the sheet conveying path SH2, and a toner image is transferred to the secondary transfer region Q4 by a registration roll Rr as an example of a sheet feeding timing adjusting member. In time, the toner is conveyed to the secondary transfer region Q4 through the medium guide member SG.

  The medium guide member SG is fixed to the image forming apparatus main body U3 together with the registration roll Rr.

  The toner image on the intermediate transfer belt B is transferred to the recording paper S by the secondary transfer device T2 when passing through the secondary transfer region Q4. In the case of a full-color image, the toner images primarily transferred onto the surface of the intermediate transfer belt B are secondarily transferred onto the recording paper S all at once.

  The intermediate transfer belt B after the secondary transfer is cleaned, that is, cleaned by a belt cleaner CLB as an example of an intermediate transfer body cleaner. The secondary transfer roll T2B and the belt cleaner CLB are supported so as to be separated from and in contact with the intermediate transfer belt B.

  A transfer device (T1 + B + T2 + CLB) for transferring the image on the surface of the photosensitive drums Py to Pk onto the recording paper S by the primary transfer rolls T1y, T1m, T1c, T1k, the intermediate transfer belt B, the secondary transfer device T2, the belt cleaner CLB, and the like. ) Is configured.

The recording sheet S on which the toner image is secondarily transferred is conveyed to a fixing device F through a sheet conveying belt BH as an example of a medium conveying member before fixing. The fixing device F has a heating roll Fh as an example of a heat fixing member and a pressure roll Fp as an example of a pressure fixing member, and is fixed by a region where the heating roll Fh and the pressure roll Fp are in pressure contact with each other. Region Q5 is formed.
The toner image on the recording paper S is heated and fixed by the fixing device F when passing through the fixing region Q5. A transport path switching member GT1 is provided on the downstream side of the fixing device F. The conveyance path switching member GT1 selectively selects the recording sheet S conveyed through the sheet conveyance path SH2 and heated and fixed in the fixing region Q5, either on the sheet discharge path SH3 or the sheet reversing path SH4 side of the sheet processing apparatus U4. Switch. The sheet S conveyed to the sheet discharge path SH3 is conveyed to the sheet conveyance path SH5 of the sheet processing apparatus U4.

  A curl correction device U4a is disposed in the middle of the sheet conveyance path SH5, and a switching gate G4 as an example of a conveyance path switching member is disposed in the sheet conveyance path SH5. The switching gate G4 causes the first curl correction member h1 or the second curl correction member h2 to move the recording sheet S conveyed from the sheet conveyance path SH3 of the image forming apparatus main body U3 according to the direction of curving, so-called curl. Transport to either side of The recording paper S conveyed to the first curl correction member h1 or the second curl correction member h2 is curled when passing. The recording sheet S with the curl corrected is in a so-called face-up state in which the image fixing surface of the sheet faces upward from a discharge roll Rh as an example of a discharge member to a discharge tray TH1 as an example of a discharge unit of the paper processing device U4. It is discharged at.

  The sheet S conveyed to the sheet reversing path SH4 side of the image forming apparatus main body U3 by the conveyance path switching member GT1 passes through the conveyance direction regulating member constituted by an elastic thin film member, so-called mylar gate GT2. Then, it is conveyed to the sheet reversing path SH4 of the image forming apparatus main body U3.

  A sheet circulation path SH6 and a sheet reversing path SH7 are connected to the downstream end of the sheet reversing path SH4 of the image forming apparatus body U3, and a mylar gate GT3 is also disposed at the connecting portion. The sheet conveyed through the switching gate GT1 to the sheet conveying path SH4 is conveyed to the sheet reversing path SH7 side of the sheet processing apparatus U4 through the mylar gate GT3. When performing duplex printing, the recording paper S that has been transported through the paper reversing path SH4 passes through the Mylar gate GT3 as it is, is transported to the paper reversing path SH7, and then transported in the opposite direction. When switched back, the transport direction is regulated by the mylar gate GT3, and the recording sheet S that has been switched back is transported to the paper circulation path SH6. The recording sheet S conveyed to the sheet circulation path SH6 is retransmitted to the transfer area Q4 through the sheet feeding path SH1.

  On the other hand, when the recording paper S conveyed on the paper reversing path SH4 is switched back after the trailing edge of the recording paper S passes through the Mylar gate GT2 and before passing through the Mylar gate GT3, the Mylar gate GT2 causes the recording paper S The transport direction is regulated, and the recording paper S is transported to the paper transport path SH5 with the front and back sides reversed. The recording sheet S whose front and back sides are reversed is subjected to curl correction by the curl correction member U4a, and then the image fixing surface of the sheet S faces downward in the sheet discharge tray TH1 of the sheet processing apparatus U4, so-called face-down state. Can be discharged.

  A sheet transport path SH is constituted by the elements indicated by the symbols SH1 to SH7. Further, the sheet conveying device SU is constituted by the elements indicated by the symbols SH, Ra, Rr, Rh, SG, BH, GT1 to GT3.

(Configuration of charger according to this embodiment)
Next, the configuration of the charger according to the present embodiment will be described. Here, the charger CCk will be described as an example, but the chargers CCy, CCm, and CCc are configured similarly to the charger CCk.

  FIG. 3 is a perspective view showing the configuration of the charger according to the present embodiment. 4A and 4B are cross-sectional views of main parts of the charger according to the present embodiment. FIG. 4A is an explanatory diagram of main parts on the right side of the charger, and FIG. 4B is an explanatory diagram of main parts on the left side of the charger. It is.

  3 and 4, the charger CCk according to the present embodiment includes a shield electrode 1 as an example of a U-shaped surrounding electrode member that extends in the front-rear direction and is open on the photosensitive drum Pr to Pk side. The shield electrode 1 has an upper wall 2 and a left side wall 3 and a right side wall 4 that extend downward from the left and right sides of the upper wall 2.

  An air supply port 2 a extending in the front-rear direction is formed on the left side of the upper wall 2. A spring claw 2b is formed at the front end of the upper wall 2, and an end member retaining hole 2c is formed at the rear end. In FIG. 4B, a counter electrode terminal 3 a is formed at the rear end portion of the left side wall 3, and a predetermined counter electrode voltage is applied from the power supply circuit E of the image forming apparatus U. FIG. 3 shows the charger CCk with the rear cover 5 removed as an example of a mounting protection member.

  In FIG. 3, a front end member 6 is fixedly supported at the front end portion of the shield electrode 1. On the right side of the rear end portion of the front end member 6, a front rotation shaft support portion 6a protruding rightward is formed. On the front side of the front end member 6, a pair of spring mounting portions 6 b are formed that protrude outward in the left and right directions. In FIG. 3, only the right spring mounting portion 6a is shown. A mesh electrode stretching spring 7 is mounted on the spring mounting portion 6b. The mesh electrode stretching spring 7 has a claw hooking portion 7a at an upper portion thereof, and the claw hooking portion 7a is caused to enter a space between the upper wall 2 and the front end member 6 to be brought into contact with the spring claw portion 2b. It is possible to hook. The mesh electrode stretching spring 7 has an electrode claw portion 7b formed in the lower part.

  3 and 4, the rear end member 8 is fixedly supported at the rear end portion of the shield electrode 1. The rear side end member 8 includes a projection (not shown) mounted on a front side movement restriction groove (not shown) formed on the left and right side walls 3 and 4, and a claw member 8a hooked on the end member retaining hole 2c. It is fixedly supported at the rear end of the shield electrode 1. On the right side of the rear end member 8, a rear rotation shaft support portion 8b protruding rightward is formed corresponding to the front rotation shaft support portion 6a.

  A discharge electrode terminal protection part 8c and a counter electrode terminal protection part 8d for protecting the counter electrode terminal 3a are formed at the rear end part of the rear end member 8 so as to protrude rearward. At the lower part of the rear end member 8, a mesh electrode one end support portion 8e protruding downward is formed. Further, in FIGS. 4A and 4B, the rear end member 8 is formed with a pair of discharge cleaning pressing release portions 8 f protruding into the shield electrode 1.

  In FIG. 4, a discharge electrode member 11 extending in the front-rear direction is supported between the pair of front and rear end members 6, 8 in the shield electrode 1. In the present embodiment, the discharge electrode member 11 is made of a tungsten member having a diameter of 40 [μm] and a length of 396.2 ± 0.7 [mm]. It is possible to change arbitrarily according to.

  That is, any material that can be used as the discharge electrode, such as tungsten, molybdenum, tantalum, or gold plating, can be used. The discharge electrode member 11 is provided with an electrode terminal (not shown) accommodated in the discharge electrode terminal protection portion 8c at the rear end, and is supplied with power from the power supply circuit E of the image forming apparatus U. In the present embodiment, the power supplied to the discharge electrode member 11 is controlled at a constant current, and 700 [−μA] is supplied. However, the constant current control and the constant voltage control can be changed according to the design or the like. In addition, the supplied current value and voltage value can be appropriately changed.

  FIG. 5 is an explanatory diagram showing the configuration of the mesh electrode member according to the present embodiment.

  3 to 5, a mesh electrode member 12 is provided between the end members 6 and 8 at the opening position on the lower side of the shield electrode 1, that is, a charged region that is an opposite region of the image carriers Py to Pk. It is supported. The mesh electrode member 12 is formed at the center mesh portion 12a, the frame portion 12b surrounding the mesh portion 12a, the front supported portion 12c formed on the front side of the frame portion 12b, and the frame portion 12b on the rear side. And a rear-side supported portion 12d. At the front end of the front supported portion 12c, a pair of left and right claw catching holes 12c1 formed corresponding to the electrode claw portions 7b of the mesh electrode stretching spring 7 is formed. The hooking hole 12c1 also has a function of an energizing part.

  The rear supported portion 12d is formed with a mounting hole 12d1 for mounting to the mesh electrode one end supporting portion 8e. Therefore, the mesh electrode member 12 of the present embodiment has the mounting hole 12d1 fixed to the mesh electrode one end support portion 8e and is mounted to the mesh electrode stretching spring 7. Supported in a tensioned state.

  Further, the mesh electrode member 12 is electrically connected to the shield electrode 1 via a conductive mesh electrode stretching spring 7, and the mesh electrode member 12 and the shield electrode 1 are opposed to each other in the present embodiment. An electrode member (1 + 12) is configured. In this embodiment, the voltage applied to the counter electrode member (1 + 12) is changed and controlled depending on the environment such as temperature and humidity, but the counter electrode voltage of about −700 [V] to −800 [V]. Is applied.

  In FIG. 5, the mesh electrode member 12 of the present embodiment is made of stainless steel, and a surface layer made of tetrahedral amorphous carbon as an example of a coating material is formed on the surface facing the discharge electrode 11. That is, it is coated. The surface layer is formed with a film thickness of 0.05 [μm], for example. Hereinafter, tetrahedral amorphous carbon is simply referred to as ta-C. Here, in the mesh electrode member 12, a surface layer of ta-C is formed on the inner surfaces of the mesh portion 12a and the frame portion 12b, that is, on the surface facing the discharge electrode member 11.

  The ta-C is semiconductive having a volume resistivity of about 108 [Ω · cm] to 1010 [Ω · cm] depending on the film thickness, and has a slightly higher electric resistance than the conductor. It is formed not on the entire surface of the member 12 but only on a part of the surface where the problem due to the discharge product becomes significant. That is, in order to suppress an increase in the electrical resistance of a portion of the claw hooking portion 12c1 as an example of the energization portion to which power is supplied to the mesh electrode member 12, a surface layer formed by ta-C is formed on the front supported portion 12c. It has not been.

  In the present embodiment, in addition to the mesh electrode member 12, a ta-C surface layer is also formed on the surface of the discharge electrode member 11 and the inner surface of the shield electrode 1.

  In the present embodiment, a surface layer made of ta-C is formed only on the surface facing the discharge electrode member 11. However, in order to further suppress the adhesion and re-release of the discharge product, the mesh electrode member 12 is used. It is also possible to form a film on both sides. In this case, the thickness of the surface layer formed by ta-C formed on the surface facing the discharge electrode member 11 is set to the thickness of the surface layer formed by ta-C formed on the surface facing the image carriers Py to Pk. May be thicker.

  That is, the surface facing the discharge electrode member 11 has a large amount of discharge products, so that so-called sputtering is likely to occur, and it is necessary to have a predetermined film thickness or more. Since the amount of the object and the load due to sputtering are small, the film thickness may be thin, and the film formation time and raw materials for manufacturing can be reduced, and the cost can be reduced. That is, it is possible to make the surface layer by ta-C into a different film thickness on the front surface and the back surface.

  In the present embodiment, the ta-C surface layer is formed on the inner surfaces of the mesh electrode member 12, the discharge electrode member 11, and the shield electrode 1. However, as the charger CCk according to the present embodiment, the mesh electrode member is used. 12, the ta-C surface layer should just be formed in at least one place among the inner surfaces of the discharge electrode member 11 and the shield electrode 1.

  The ta-C thin film having the SP3 structure of carbon atoms as the main structure on the mesh electrode member 12 is ionized by converting carbon atoms or carbon atoms and other desired atoms or other atoms into plasma. The formed atoms were attached to the surface of the mesh electrode member 12 to form.

  As the ta-C thin film, the SP3 structure is preferably about 40% to 85% from the viewpoint of conductivity and wear resistance. For example, it can be done with FCVA technology, ie Filtered Cathodic VacuumArcTechnology. The FCVA technology itself is conventionally known. For example, although it is not a charger, Japanese Patent Laid-Open No. 2001-195717 for forming a wear-resistant film on a magnetic disk and Japanese Patent Laid-Open No. 2005-173141 for forming a wear-resistant film on the surface of a developing roll. Detailed description will be omitted because there are no.

(Configuration in which the surface on which the surface layer of ta-C is formed is heated)
Next, the structure which heats the surface in which the surface layer by ta-C was formed is demonstrated.

  The charger CCk according to the present embodiment includes heating devices 50, 52, and 54 as heating means for heating the surface on which the surface layer of ta-C is formed.

  A heating device 50 is provided on the outer surface of the upper wall 2 of the shield electrode 1 to heat the inner surface of the shield electrode 1 on which a surface layer of ta-C is formed. The heating device 50 is composed of a surface heater and heats the outer surface of the upper wall 2 of the shield electrode 1. By heating the outer surface of the upper wall 2 of the shield electrode 1, the inner surface of the shield electrode 1 on which the surface layer of ta-C is formed is heated by the heat conduction of the shield electrode 1.

  A heating device 52 that heats the surface of the mesh electrode member 12 having a surface layer of ta-C formed on the front supported portion 12c and the rear supported portion 12d formed at the longitudinal ends of the mesh electrode member 12. Is provided.

  Note that the surface of the mesh electrode member 12 on which the surface layer by ta-C is formed is the surface of the discharge electrode member 11 in the configuration in which the surface layer by ta-C is formed only on the surface facing the discharge electrode member 11. In a configuration in which a surface layer made of ta-C is formed on a surface facing the discharge electrode member 11 and a back surface thereof, the surface facing the discharge electrode member 11 and the back surface thereof.

  The heating device 52 is composed of a surface heater, and heats the front supported portion 12c and the rear supported portion 12d. By heating the front supported portion 12c and the rear supported portion 12d, the surface of the mesh electrode member 12 on which the surface layer of ta-C is formed is heated by the heat conduction of the mesh electrode member 12.

  FIG. 6 is a schematic view showing a heating device 54 that heats the surface of the discharge electrode member 11 on which a surface layer of ta-C is formed.

  As shown in FIG. 6A, a heating device 54 for heating a part of the discharge electrode member 11 is provided in the vicinity of the support portion of the discharge electrode member 11 (not shown). When a part of the discharge electrode member 11 is heated, the surface of the discharge electrode member 11 on which the surface layer of ta-C is formed is heated by the heat conduction of the discharge electrode member 11.

  As the charger CCk according to the present embodiment, a ta-C surface layer may be formed at least at one of the inner surfaces of the mesh electrode member 12, the discharge electrode member 11, and the shield electrode 1, and ta The surface on which the surface layer is not formed by -C may be configured not to include the heating devices 50, 52, and 54 for heating the surface.

  As shown in FIG. 6B, the discharge electrode member according to the present embodiment may be a multi-needle electrode 13 formed in a zigzag shape. In this configuration, a surface layer of ta-C is formed at the tip portion 13 a of the multi-needle electrode 13, and the heating device 54 heats a part of the multi-needle electrode 13, so that the heat conduction of the multi-needle electrode 13 is performed. As a result, the tip portion 13a of the multi-needle electrode 13 on which the surface layer of ta-C is formed is heated.

  Further, the heating devices 50, 52, and 54 are configured to heat at the time of non-discharge when no discharge is generated between the discharge electrode member 11 and the counter electrode member (1 + 12).

  The non-discharge occurs, for example, when the image forming apparatus U is not performing an image forming operation. During standby, the rotation of the photosensitive drum Pk for forming an image is not performed and is normally stopped.

  The heating devices 50, 52, and 54 determine the heating time based on the discharge time of the discharge electrode member 11. For example, if the discharge time of the discharge electrode member 11 is increased, the heating time of the heating devices 50, 52, 54 is increased. If the discharge time of the discharge electrode member 11 is short, the heating time of the heating devices 50, 52, 54 is increased. Will be reduced.

  Since the discharge time of the discharge electrode member 11 is proportional to the operation time of the image forming operation in the image forming apparatus U, for example, the discharge time of the discharge electrode member 11 is indirectly measured by measuring the number of cycles of the photosensitive drum Pk. And the heating time of the heating devices 50, 52, and 54 may be determined.

  Further, a temperature sensor (not shown) is provided, and the temperature sensor can detect the inner surfaces of the mesh electrode member 12, the discharge electrode member 11, and the shield electrode 1. Based on the temperature detected by the temperature sensor, the heating devices 50, 52, and 54 are controlled to manage the temperatures of the inner surfaces of the mesh electrode member 12, the discharge electrode member 11, and the shield electrode 1.

  Further, the heating temperature of the heating devices 50, 52, and 54 is set to be higher than the boiling point and the sublimation point (that is, the temperature at which the deposits are vaporized) of the deposit attached to the surface heated by the heating devices 50, 52, and 54. Yes. For example, N205 (anhydrous nitric acid) is considered as the deposit, and the sublimation point of N205 (anhydrous nitric acid) is 32 ° C.

  In addition, when the heating devices 50, 52, and 54 are heating the surface on which the surface layer of ta-C is formed, the photosensitive drum Pk may be rotated without image formation.

  By rotating the photosensitive drum Pk, an air flow is generated, and the discharge products evaporated by the heating of the heating devices 50, 52, and 54 are prevented from adhering to the photosensitive drum Pk.

  The heating by the heating devices 50, 52, and 54 may not be performed when the charger CCk is not discharged (while the image forming apparatus U is on standby), but when the charger CCk is discharged (image forming operation of the image forming apparatus U). Middle).

  Moreover, as a structure of the heating apparatuses 50, 52, and 54, various structures can be considered and it is not limited to the said structure.

(Configuration for cleaning discharge electrode member 11 and counter electrode member (1 + 12))
Next, a configuration for cleaning the discharge electrode member 11 and the counter electrode member (1 + 12) will be described.

  3 and 4, on the right side outside the shield electrode 1, a rotary shaft 16 extending in the front-rear direction is rotatably supported between the pair of front and rear rotary shaft support portions 6a and 8b. The rear portion of the rotary shaft 16 extends rearward through the rear rotary shaft support portion 8b, and a gear (not shown) is attached to the rear end portion, and rotation is transmitted from a motor (not shown). A spiral thread 16 a is formed on the outer periphery of the rotating shaft 16.

  An electrode cleaning member 17 is accommodated inside the shield electrode 1 and the mesh electrode member 12. The electrode cleaning member 17 includes a cleaning member main body 18, a mesh electrode cleaning body 19 fixedly supported by the cleaning member main body 18, and a discharge electrode cleaning body 21 movably supported by the cleaning member main body 18. The cleaning member main body 18 includes an upper wall sandwiching portion 18a that is disposed above the air supply port 2a and sandwiches the upper wall 2, and includes a right wall 4 and a frame portion 12b of the mesh electrode member 12. A movement transmitting portion 18b that extends downward through a gap therebetween and extends around the right side wall 4 to the rotating shaft 16 is provided. A screw fitting portion 18c that is screwed to the screw thread 16a of the rotating shaft 16 is formed at the tip of the movement transmitting portion 18b. In FIG. 4, a contact protrusion 18 d for reducing frictional resistance is formed between the cleaning member main body 18 and the upper wall 2.

  The mesh electrode cleaning body 19 includes a frame portion sandwiching portion 19 a that sandwiches the frame portion 12 b of the mesh electrode member 12, and a mesh electrode cleaning portion 19 b that contacts the inner surface of the mesh electrode member 12. The mesh electrode cleaning unit 19b is formed with a so-called cleaning brush in which a large number of cleaning hairs are implanted. A position restricting portion 19c protruding downward is formed below the mesh electrode cleaning portion 19b.

  The discharge electrode cleaning body 21 disposed below the position restricting portion 19c is supported by the discharge electrode cleaning body main body 21a and the discharge electrode cleaning body main body 21a, and discharges in contact with the discharge electrode 11 for cleaning. Part 21b. The discharge electrode cleaning part 21b of this embodiment is comprised with the cloth-like material. The discharge electrode cleaning body main body 21a is urged by a spring (not shown) in a direction in which the discharge electrode cleaning portion 21b is pressed against the discharge electrode 11, and the discharge electrode cleaning body main body 21a is positioned by the position restricting portion 19c. The discharge electrode cleaning part 21b is pressed against the discharge electrode 11 with a predetermined force.

  Therefore, by rotating the rotating shaft 16 forward or backward, the movement transmitting portion 18b moves forward or backward, and the electrode cleaning member 17 is guided by the upper wall sandwiching portion 18a or the frame portion sandwiching portion 19a. It is guided and moves in the front-rear direction. As the electrode cleaning member 17 moves, the mesh electrode member 12 and the discharge electrode member 11 are cleaned by the mesh electrode cleaning part 19b and the discharge electrode cleaning part 21b. In the present embodiment, the motor is driven every time 5000 sheets are printed, that is, every 5 kPV, and the cleaning by the electrode cleaning member 17 is automatically executed.

  Further, a cleaning unit (not shown) is provided for cleaning by contacting the inner peripheral surface of the shield electrode 1.

  In the present embodiment, when the electrode cleaning member 17 is moved to the standby position shown in FIG. 3, the discharge cleaning pressing release portion 8f of the rear end member 8 is connected to the discharge electrode cleaning body main body 21a and the position regulating portion 19c. , The discharge electrode cleaning part 21b is held in a state of being separated from the discharge electrode 11, and the electrode cleaning member 17 moves forward, whereby the discharge electrode pressing release part 8f becomes the discharge electrode cleaning body. It is comprised so that it may detach | leave from between the main body 21a and the position control part 19c. Therefore, when the cleaning operation of the electrodes 11 and 12 is completed and the image forming operation is performed, the discharge electrode 11 is set at a predetermined position by moving to the standby position, and stable discharge is possible. At the same time, during the cleaning operation, the discharge electrode pressing release portion 8f is detached and the discharge electrode cleaning portion 21b is pressed against the discharge electrode 11 to be cleaned.

  The heating devices 52 and 54 heat the inner surface of the shield electrode 1 on which the surface layer of ta-C is formed, the surfaces of the mesh electrode member 12 and the discharge electrode member 11 before the electrode cleaning member 17 and the cleaning unit clean. It is supposed to be.

  In addition, as the charger CCk according to the present embodiment, the configuration for cleaning the inner peripheral surfaces of the mesh electrode member 12, the discharge electrode member 11, and the shield electrode 1 is not essential, and the configuration does not include this configuration. Also good.

(Configuration for transferring air as an example of gas to the surface on which the surface layer of ta-C is formed)
Next, the structure which transfers the air as an example of gas to the surface in which the surface layer by ta-C was formed is demonstrated.

  In FIG. 2, an air outlet 60 is formed in the image forming apparatus main body U3 of the present embodiment on the upper left side of the charger CCk.

  The air outlet 60 is provided with a purifier for purifying outside air, a so-called filter 61. In the image forming apparatus main body U3, a blower 62 as an example of a gas transfer device is disposed in the vicinity of the air outlet 60, and the blower 62 passes outside air into the image forming apparatus main body U3 through the air outlet 60. It comes to capture.

  A duct 66 through which air can flow is disposed between the latent image forming device ROSK and the developing unit GK. The duct 66 communicates with an air discharge port (not shown). This air discharge port is provided with a purifier, a so-called filter.

  A duct 68 through which air can flow is also disposed between the developing unit GK and the intermediate transfer belt B. This duct 68 leads to an air discharge port (not shown). This air discharge port is provided with a purifier, a so-called filter.

  In addition, a duct 70 through which air can flow is disposed above the cleaner CLk. The duct 70 communicates with an air discharge port (not shown). This air discharge port is provided with a purifier, a so-called filter.

  The air drawn into the image forming apparatus main body U3 from the air outlet 60 by the blower 62 passes through the inside of the charger CCk via the air supply port 2a, passes through the mesh electrode member 12, and passes through the reticule CCk. It is discharged from below.

  The air discharged from below the charger CCk passes between the latent image forming device ROSK and the developing device GK, flows into the duct 66, is cleaned by a filter from the air discharge port, and is discharged to the outside air. .

  Further, the air discharged from below the charger CCk flows downward along the surface of the photosensitive drum Pk, passes between the developing unit GK and the intermediate transfer belt B, flows into the duct 68, and discharges the air. It is cleaned with a filter from the outlet and discharged to the outside air.

  Further, the air discharged from the lower side of the charger CCk flows along the surface of the photosensitive drum Pk. When the air reaches the cleaner CLk side, it flows into the duct 70 and is cleaned by the filter from the air discharge port to the outside air. Released.

  Thus, the air drawn into the image forming apparatus main body U3 from the air outlet 60 passes through the inside of the charger CCk through the air supply port 2a and is released to the outside air from the air discharge port. , Air flows along the surface on which the surface layer of ta-C is formed.

  An example of the gas transfer device is not limited to a blower that takes in air from the air outlet 60, that is, a take-in fan, and is, for example, a discharge fan that is arranged close to the air discharge port and discharges from the air discharge port. May be.

  Further, the blower 62 is configured to send air at the time of non-discharge when no discharge is generated between the discharge electrode member 11 and the counter electrode member (1 + 12).

  The non-discharge occurs, for example, when the image forming apparatus U is not performing an image forming operation. During standby, the rotation of the photosensitive drum Pk for forming an image is not performed and is normally stopped.

  The blower 62 determines the blow time based on the discharge time of the discharge electrode member 11. For example, if the discharge time of the discharge electrode member 11 is increased, the blow time of the blower 62 is increased, and if the discharge time of the discharge electrode member 11 is short, the blow time of the blower 62 is decreased.

  Since the discharge time of the discharge electrode member 11 is proportional to the operation time of the image forming operation in the image forming apparatus U, for example, the discharge time of the discharge electrode member 11 is indirectly measured by measuring the number of cycles of the photosensitive drum Pk. May be measured and the blowing time of the blower 62 may be determined.

  The blower 62 can suck outside air at a wind speed of about 1 m / sec and blow it to the charger CCk, for example. Note that an air flow meter may be provided to measure the air flow, and the blower 62 may be controlled based on the air flow measured by the air flow meter.

  Moreover, when the air blower 62 is blowing along the surface in which the surface layer by ta-C was formed, the structure which rotates the photosensitive drum Pk may be sufficient.

  By rotating the photosensitive drum Pk, an air flow is generated, and the discharge products evaporated by the heating of the heating devices 50, 52, and 54 are prevented from adhering to the photosensitive drum Pk. The rotational speed of the photosensitive drum Pk is controlled according to the amount of air blown from the blower 62.

  Further, the blower 62 is generated between the discharge electrode member 11 and the counter electrode member (1 + 12) rather than at the time of discharge when the discharge generated between the discharge electrode member 11 and the counter electrode member (1 + 12) is made. The air flow rate is adjusted so that the air flow rate during non-discharge when no discharge is performed increases.

  FIG. 7 shows the gas re-emission characteristics after the discharge is stopped when the surface layer of ta-C is formed on the inner surface of the shield electrode 1 and when the surface layer of ta-C is not formed on the inner surface of the shield electrode 1. It is the graph compared.

  The vertical axis represents the value of the gas concentration of the gas in which the discharge product such as nitrogen oxide NOx adhering to the inner surface of the shield electrode 1 is vaporized and re-released. The horizontal axis shows the passage of time when the stop time when the discharge is stopped is taken as zero. The solid line in the graph shows the case where the surface layer made of ta-C is formed on the inner surface of the shield electrode 1, and the dotted line shows the case where the surface layer made of ta-C is not formed on the inner surface of the shield electrode 1. This comparison result was measured in the vicinity of the inner surface of the shield electrode 1.

  As a result, when a surface layer made of ta-C is formed on the inner surface of the shield electrode 1, it can be seen that the amount of gas released immediately after the discharge is stopped (particularly 10 minutes after the discharge is stopped) and then rapidly decreases.

  In consideration of such characteristics, as shown in FIG. 8, the air volume of the blower 62 and the rotational speed of the photosensitive drum Pk are controlled. That is, when the discharge is stopped or immediately after the discharge is stopped, the air volume of the blower 62 and the rotational speed of the photosensitive drum Pk are increased. When the discharge is stopped or immediately after the discharge is stopped, the air volume of the blower 62 and the photosensitive drum Pk are set to have a peak. Thereafter, the air volume of the blower 62 and the rotational speed of the photosensitive drum Pk are decreased stepwise. Finally, the blower 62 and the photosensitive drum Pk are stopped, and unnecessary operations of the blower 62 and the photosensitive drum Pk are not performed.

  Thereby, noise and power consumption are minimized while suppressing deterioration of the surface of the photosensitive drum Pk due to re-released gas.

  In addition, as the charger CCk according to the present embodiment, the configuration having the blower 62 is not essential, and may be a configuration that does not have this configuration.

(Operation of this embodiment)
Next, the operation of this embodiment will be described.

  In the image forming apparatus U according to the present embodiment, when a potential difference is generated by applying a voltage to the discharge electrode member 11 and the counter electrode member (1 + 12), a discharge is generated and the surfaces of the photosensitive drums Py to Pk are exposed. Charged. In this embodiment, charges are uniformly supplied to the photosensitive drums Py to Pk by the mesh electrode member 12 and are uniformly charged.

  During discharge in the charger CCk, discharge products such as ozone O3 and nitrogen oxides NOx are generated inside the charger CCk. These discharge products adhere to the discharge electrode member 11, the shield electrode 1, or the mesh electrode member 12, or the discharge product reacts with the discharge electrode member 11 or the shield electrode 1 mesh electrode member 12 to form a metal oxide, so-called Rust.

  If the oxide adheres or rusts, the oxide or the like is an insulator, which may cause an abnormal charging property. In particular, when rust occurs on the mesh electrode member 12, the ability to equalize the charge is reduced. However, in this embodiment, the occurrence of rust of the mesh electrode member 12 is reduced by the surface layer of ta-C which has oxidation resistance and low reactivity. Moreover, since the surface of ta-C is smooth, even when the discharge product adheres to the discharge electrode member 11, the shield electrode 1, and the mesh electrode member 12, the mechanical coupling force is small.

  In the present embodiment, the heating device 50 heats the inner surface of the shield electrode 1 on which the surface layer of ta-C is formed. The heating device 52 heats the surface of the mesh electrode member 12 on which the surface layer of ta-C is formed. The heating device 54 heats the surface of the discharge electrode member 11 on which the surface layer of ta-C is formed.

  As a result, the discharge products adhering to the inner surface of the shield electrode 1, the surface of the mesh electrode member 12 and the surface of the discharge electrode member 11 are evaporated, and from the inner surface of the shield electrode 1, the surface of the mesh electrode member 12 and the discharge electrode member 11. Released.

  Further, since the air is supplied from the air supply port 2a to the charger CCk of the present embodiment, and the air flows along the inner surface of the shield electrode 1, the surface of the mesh electrode member 12, and the surface of the discharge electrode member 11, The discharge products adhering to the inner surface of the shield electrode 1, the surface of the mesh electrode member 12, and the surface of the discharge electrode member 11, and the discharge products evaporated by the heating of the heating devices 50, 52, and 54 are discharged together with air.

  In this way, the discharge products attached to the inner surface of the shield electrode 1, the surface of the mesh electrode member 12, and the surface of the discharge electrode member 11 are heated by the heating devices 50, 52, and 54, and the inner surface of the shield electrode 1, the mesh electrode member. 12 and the surface of the discharge electrode member 11 are discharged to reduce charging defects.

  Further, since the discharge product discharged from the inner surface of the shield electrode 1, the surface of the mesh electrode member 12, and the surface of the discharge electrode member 11 is discharged by the blower of the blower 62, the discharge product contaminates the photosensitive drum Pk. Therefore, it is possible to suppress the deterioration of the photosensitive drum Pk.

  Hereinafter, the results of experiments performed based on the configuration of the present embodiment are shown below.

(Experiment 1)
In Experiment 1, in the configuration in which the surface layer of ta-C is formed on the discharge electrode member 11 and the other conditions are the same, when the discharge electrode member 11 is not heated, the discharge electrode member 11 is 50 ° C., 100 ° C., 150 ° C. The transition of discharge unevenness when heated to ℃ was compared. FIG. 9 is a graph showing the comparison results.

  It was found that when the discharge electrode member 11 is heated, an increase in discharge unevenness is suppressed, and when the discharge electrode member 11 is further heated to 100 ° C. or higher, the effect is high.

(Experiment 2)
In Experiment 2, in the configuration in which the surface layer of ta-C was formed on the inner surfaces of the mesh electrode member 12 and the shield electrode 1, the printing operation was stopped after outputting about 300k cycles with the number of cycles of the photosensitive drum Pk. Then, after entering the standby state under the following conditions, when printing an image of Cin 20%, screen 200 cluster dots at a speed of 75 mm / sec, the presence or absence of white spots (parking deletion) at the charger CCk position was confirmed. . In the parking deletion, the color difference between the generation part and the non-generation part was measured, and one or more was determined to be generated.

  FIG. 10 shows three conditions during standby; (1) a ta-C surface layer only formed on the inner surfaces of the mesh electrode member 12 and the shield electrode 1 (Comparative Example 1); Equipped with an electrode cleaning member for cleaning the inner surfaces of the electrode member 12 and the shield electrode 1 (Comparative Example 2), (3) No electrode cleaning member, but heated and blown during standby (an example of the configuration of this embodiment) ) Is a graph showing the state of occurrence of parking deletion.

  In the case of the comparative example 1, generation | occurrence | production of parking deletion can be suppressed by carrying out ventilation for 10 hours. In the case of the comparative example 2, generation | occurrence | production can be suppressed by blowing air for 3 hours. In the case of the structure of this embodiment, generation | occurrence | production can be suppressed by performing ventilation and heating for 10 minutes.

  In this embodiment, the operation time is 15 seconds when the number of cycles of the photosensitive drum Pk is less than 100 k cycles, 3 minutes when the number of cycles of the photosensitive drum Pk is 100 k or more and less than 200 k, and the number of cycles of the photosensitive drum Pk is 200 k or more and 300 k. Is less than 6 minutes, and the number of cycles of the photosensitive drum Pk is preferably 10 minutes when the number of cycles is 300 k or more.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation, a change, and improvement are possible as follows.

  In the embodiment, the present invention is not limited to a copying machine as an example of an image forming apparatus, and can be applied to an image forming apparatus such as a printer or a FAX. Further, the present invention is not limited to a color image forming apparatus, and can be applied to a monochrome image forming apparatus. Further, the present invention is not limited to a tandem type image forming apparatus, and can be applied to a rotary type image forming apparatus.

  Moreover, in the said embodiment, although the discharge electrode member 11 illustrated the case of one thread-like member, it is not limited to this, It can also be set as the structure etc. which have two thread-like discharge electrode members. is there.

Further, the chargers CCy, CCm, CCc, and CCk may be configured without the mesh electrode member 12.
In the above-described embodiment, the charger as an example of the discharger has been illustrated. However, the present invention is not limited to this, and the charger can be used as a static eliminator or an auxiliary charger as another example of the discharger. For example, the configuration of the chargers CCy, CCm, CCc, CCk as radiators is used for a charger disposed between the primary transfer rolls T1y, T1m, T1c, T1k and the cleaners CLy, CLm, CLc, CLk. May be.

  In the embodiment, the air flow path is not limited to the structure described in the embodiment, and any flow path structure may be used. At this time, the position of the air supply port 2a can also be changed according to the flow path. It is also possible to increase the flow rate of air blowing and discharging during standby.

  In the above-described embodiment, the charger CCk is configured to be detachable from the image forming apparatus U as an image holding unit, but is not limited to this configuration, and may be configured to be fixedly supported by the image forming apparatus U. .

  In the said embodiment, the structure of the electrode cleaning member 17 is not limited to the structure illustrated by embodiment, Arbitrary structures are employable according to a design. For example, it is possible to adopt a configuration in which the electrode members 1, 11, and 12 are cleaned by a user opening the inside and manually operating the operation unit, instead of a configuration that automatically cleans. Also, the configuration of the brush, cloth, etc. can be changed to an arbitrary cleanable configuration, such as a sponge. Furthermore, it is also possible to have a configuration in which both surfaces of the mesh electrode member 12 can be cleaned by providing a cleaning portion between the frame portion sandwiching portions 19a.

  In the above embodiment, the surface layer composed only of ta-C has been exemplified. However, due to the configuration of the charger, for example, when the current-carrying portion and the electrode are combined, the mesh electrode member is fed with power as the counter electrode terminal 3a. When the current-carrying part to be used is provided, or when the resistance is affected by the resistance of the counter electrode, the SP3 ratio is reduced, N2, Cr, Ti etc. Is added (added) to adjust conductivity and oxidation resistance, and a ta-C film having an SP3 structure of carbon atoms as a main structure, or a film formed with DLC (diamond-like carbon), usage conditions and purpose Depending on the situation, it may be changed appropriately. Note that the ratio of the SP3 structure, the thickness of the thin film, whether it is formed on both the front surface and the back surface, or only one of them can be changed depending on the design.

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present embodiment. FIG. 2 is a schematic diagram showing the configuration of the image carrier unit according to the present embodiment. FIG. 3 is a perspective view showing the configuration of the charger according to the present embodiment. 4A and 4B are cross-sectional views of main parts of the charger according to the present embodiment. FIG. 4A is an explanatory diagram of main parts on the right side of the charger, and FIG. 4B is an explanatory diagram of main parts on the left side of the charger. It is. FIG. 5 is an explanatory diagram showing the configuration of the mesh electrode member according to the present embodiment. FIG. 6A is a schematic view showing a heating device for heating the surface of the discharge electrode member on which the surface layer of ta-C is formed, and FIG. 6B is formed in a zigzag shape as the discharge electrode member. It is the schematic which shows the example using the made multi-needle electrode. FIG. 7 compares the gas re-emission characteristics after the discharge was stopped when the ta-C surface layer was formed on the inner surface of the shield electrode and when the ta-C surface layer was not formed on the inner surface of the shield electrode. It is a graph. FIG. 8 controls the air volume of the blower and the rotational speed of the photosensitive drum in consideration of the gas re-emission characteristic shown in FIG. FIG. 9 is a graph showing a comparison result according to Experiment 1. FIG. 10 is a graph showing a comparison result according to Experiment 2.

Explanation of symbols

1 ... Shield electrode (surrounding electrode member, counter electrode member)
11 ... discharge electrode member 12 ... mesh electrode member (counter electrode member)
17 ... Electrode cleaning members 50, 52, 54 ... Heating device (heating means)
62 ... Blower (gas transfer device)
CCy, CCm, CCc, CCk ... Charger (discharger)
E ... Power supply circuit GY, GM, GC, GK ... Developers Py, Pm, Pc, Pk ... Photosensitive drum (charged body, image holding body)
ROSy, ROSm, ROSc, ROSK ... latent image forming device T1 + B + T2 + CLB ... transfer device U ... image forming device UY, UM, UC, UK ... image carrier unit

Claims (13)

A discharge electrode member disposed opposite to the member to be charged;
A counter electrode member disposed to face the discharge electrode member;
A power supply circuit for applying a discharge voltage for generating a discharge between the discharge electrode member and the counter electrode member;
A coating material that covers at least one surface of the discharge electrode member and the counter electrode member, and that has a carbon atom, or a carbon atom and other desired atoms or other plural atoms as a main component, and has a SP3 structure of carbon atoms; ,
A heating means for heating the surface coated with the coating material;
A discharger comprising:   2. The discharger according to claim 1, wherein the heating unit heats when no discharge is generated between the discharge electrode member and the counter electrode member.   The discharger according to claim 1 or 2, wherein the heating means determines a heating time based on a discharge time of the discharge electrode member.   The discharger according to any one of claims 1 to 3, wherein a heating temperature of the heating unit is equal to or higher than a boiling point of deposits attached to the surface heated by the heating unit. An electrode cleaning member for cleaning the surface heated by the heating means;
The discharger according to any one of claims 1 to 4, wherein the heating unit heats the surface before the electrode cleaning member cleans the surface.   The discharger according to any one of claims 1 to 5, further comprising a gas transfer device that transfers gas along the surface covered with the covering material.   The discharge device according to claim 6, wherein the gas transfer device transfers gas during non-discharge when no discharge is generated between the discharge electrode member and the counter electrode member.   The discharger according to claim 6 or 7, wherein the gas transfer device determines a transfer time based on a discharge time of the discharge electrode member.   In the gas transfer device, the discharge generated between the discharge electrode member and the counter electrode member is performed more than the discharge during which the discharge generated between the discharge electrode member and the counter electrode member is performed. The discharger according to any one of claims 6 to 8, wherein there is a large amount of gas transfer when there is no non-discharge. A charger constituted by the discharger according to claim 1;
An image carrier as the member to be charged that rotates the image carrier while the heating means is heating the surface and holds an image on the surface;
An image carrier unit comprising: A charger constituted by the discharger according to any one of claims 6 to 9,
An image carrier as the member to be charged that rotates the image carrier while the gas transfer device is transferring the gas and holds an image on the surface;
An image carrier unit comprising:   The image carrier unit according to claim 11, wherein the drive control unit controls a rotation speed of the image carrier in accordance with a transfer amount of the gas of the gas transfer device. A charger constituted by the discharger according to claim 1;
An image holding body as the charged body for holding an image on the surface;
A latent image forming apparatus that forms a latent image on the surface of the image carrier charged by the charger;
A developing device for developing the latent image formed on the surface of the image carrier into a visible image;
A transfer device for transferring a visible image on the surface of the image carrier to a medium;
An image forming apparatus comprising:

Images